The invention relates to a pnp lateral transistor comprised of two regions of a second conductivity type which constitute emitter and collector regions incorporated into the surface of a semiconductor area of a first conductivity type. The portion of the semiconductor area of the first conductivity type located between these two regions constitutes the active base region.
Use of lateral pnp bipolar transistors in bipolar integrated circuits to supplement the vertical npn transistors is known. The properties of these lateral transistors, particularly with respect to cutoff frequency, current gain and noise, are clearly inferior to those of complementary vertical pnp transistors. On account of the compatibility of the manufacturing process, these lateral pnp transistors are, however, used world-wide together with vertical npn transistors in integrated circuits.
It is proposed in "IEEE Journal of Solid-State-Circuits" Volume SC-18, No. 3, June 1983, Page 273, that n-channel field-effect transistors be used as lateral npn bipolar transistors in p-well CMOS technology. This proposal may also be applied to an n-well CMOS process, in which case, the p-channel field-effect transistors located in the well are used as lateral pnp transistors.